Rigid polyurethane foam having a small cell size

Patent metadata

Field	Value
Publication number	US-2016333160-A1
Application number	US-201415112924-A
Country	US
Kind code	A1
Filing date	Jan 23, 2014
Priority date	Jan 23, 2014
Publication date	Nov 17, 2016
Grant date	—

Abstract

A rigid polyurethane (PU) foam having a number average cell size of no greater than 10

First claim

1 . A method for preparing a rigid polyurethane foam, comprising:
using carbon dioxide to provide a pressure at a first predetermined value on a polyol mixture that includes a polyol, a catalyst and a surfactant; maintaining the pressure at the first predetermined value for a first predetermined time; mixing an isocyanate with the polyol mixture to form a polyurethane reaction mixture; optionally maintaining the pressure on the polyurethane reaction mixture at the first predetermined value for a second predetermined time; increasing the pressure on the polyurethane reaction mixture from the first predetermined value to a second predetermined value greater than the first predetermined value; and releasing the polyurethane reaction mixture at a predetermined depressurization rate from the pressure after a third predetermined time to prepare the rigid polyurethane foam, where the third predetermined time is less than 30 minutes.

2 . The method of claim 1 , where the first predetermined value is from 5 megapascal (MPa) to 10 MPa at a temperature of 40 degrees Celsius (° C.) to 80° C.

3 . The method of claim 2 , where the first predetermined time is from 30 seconds (s) to 300 s.

4 . The method of claim 1 , where the second predetermined value is from greater than 10 MPa to 15 MPa at a temperature of 31° C. to 80° C.

5 . The method of claim 1 , where using carbon dioxide to provide the pressure at the first predetermined value on the polyol mixture includes using carbon dioxide in a supercritical state to provide the pressure at the first predetermined value on the polyol mixture.

6 . The method of claim 1 , where optionally maintaining the pressure on the polyurethane reaction mixture at the first predetermined value for the second predetermined time increases a carbon dioxide content of the polyurethane reaction mixture to a value of at least 20 weight percent based on the total weight of the polyol mixture after the first predetermined time.

7 . The method of claim 1 , where the polyol mixture has a number averaged functionality of at least 2 and an average hydroxyl value of at least 100 mg KOH/g.

8 . The method of claim 1 , where the polyol is selected from the group consisting of a polyether polyol, a polyester polyol or a combination thereof.

9 . The method of claim 1 , where the isocyanate is selected from the group consisting of an aliphatic isocyanate, a cycloaliphatic isocyanate, an aromatic isocyanate, a polyisocyanate prepolymer or a combination thereof.

10 . The method of claim 1 , where the predetermined depressurization rate is at least 350 MPa/s.

11 . The method of claim 1 , where mixing the isocyanate with the polyol mixture to form the polyurethane reaction mixture provides a molar ratio of isocyanate groups to hydroxyl groups of greater than 1 to 1.

12 . The method of claim 1 , further including applying a vacuum to the rigid polyurethane foam.

13 . A rigid polyurethane foam formed by the method of claim 1 .

14 . The rigid polyurethane foam of claim 13 , where the rigid polyurethane foam has a number average cell size of no greater than 10 μm.

15 . The rigid polyurethane foam of claim 13 , where the rigid polyurethane foam has a crosslink density from 1.0 to 3.0 and a weight average molecular weight (Mw) per cross-link from 300 to 900.

16 . The rigid polyurethane foam of claim 13 , where the rigid polyurethane foam has a porosity of no less than 85 percent.

17 . The rigid polyurethane foam of claim 13 , where the rigid polyurethane foam has an open cell volume content from 35 percent (%) to 95% based on all the cells in the rigid PU foam.

18 . An insulation panel formed with the rigid polyurethane foam of claim 13 .

Assignees

• Dow Global Technologies Llc
• Rohm & Haas

Inventors

• Bertucelli Luigi
• Parenti Vanni
• Li Dachao
• Liu Wei
• Chai Ning
• Wang Beilei
• Chen Cheng
• Guo Hong Fei
• Chen Jing
• Yin Yige
• Costeux Stephane
• Smith Billy G

Classifications

• C08J2205/10

  Rigid foams · CPC title

• C08J9/122 Primary

  Hydrogen, oxygen, CO2, nitrogen or noble gases · CPC title

• C08G18/1816

  having carbocyclic groups · CPC title

• C08G18/48

  Polyethers · CPC title

• C08J2203/06

  CO2, N2 or noble gases · CPC title